Portable power saw apparatus

ABSTRACT

A saw generally of the keyhole or saber saw variety. The saw blade comprises an endless band driven in one direction and having a number of cutting members which are spaced apart from the plane of the band. The saw band travels along a channel, and the cutting members extend outside the channel for cutting exposure to a work piece. The saw can be connected with a conventional portable drill for motive power, or alternatively can be provided with a self-contained motor.

States Patent [1 1 Aug.'7, 1973 1 PORTABLE POWER SAW APPARATUS [76]inventor: Walter 1). Swift, 617 E. Lee St.,

Thomaston, Ga.

[22] Filed: Jan. 3, 1972 [21] Appl. No.: 214,818

I 83/818, 83/661, 83/852, 144/73 [51] lint. C1 13271) 13/10, B27b 33/06[58] Field of Search 143/32 D, 19 E, 19 R,

143/17 R, 17 A, 135 R; 144/73, 72; 30/380, 384; 83/820, 818, 661, 852

[56] I References Cited UNITED STATES PATENTS 1,892,246 12/1932 Mohns147/73 3,338,275 8/1967 Ehlen 143/135 X 1,251,579 1/1918 Rieder 144/73427,818 5/1890 Young 144/73 Primary ExaminerDonald R. Schran m y-HaraldDrfilqrssllr z. Rqser T1 s er [57] ABSTRACT A saw generally of thekeyhole or saber saw variety. The saw blade comprises an endless banddriven in one direction and having a number of cutting members which arespaced apart from the plane of the band. The saw band travels along achannel, and the cutting members extend outside the channel for cuttingexposure to a work piece. The saw can be connected with a conventionalportable drill for motive power, or alternatively can be provided with aself-contained motor.

11) Claims, 6 Drawing Figures PATENIEUAUG mm OM FUD mw mv nv I;

DOKNBDBnBUc PORTABLE POWER SAW APPARATUS This invention relates ingeneral to saws and in particular to portable saw apparatus.

The need frequently arises in fabrication and construction for a saw ofthe so-called'keyhole variety which is usable for many purposes andwhich is especially useful for cutting out a portion of a panel or othersurface. For example, a carpenter may need to cut an opening ofrectangular or other shape in a wall to permit an object such as acabinet or the like to be installed therein. While the uses orapplications of such saws may be varied, saws of this type generally arerequired to have a relatively thin elongated blade so that cutting can,if necessary, commence from a relatively small starting hole provided inthe interior of a surface to be cut, that is, where the cut does notcommence at an outer edge of the surface.

Typical of the prior art saws which have attempted to meet these needsare such devices as the conventional manual keyhole saw, which typicallyconsists of a slender blade with.conventional cutting teeth along oneedge thereof and a handle at one end, and the wellknown saber saw, inwhich a saw blade of generally conventional design is rapidlyreciprocated by an electric motor. The conventional keyhole saw suffersthe disadvantage of any manually-operated tool namely, the sawingoperation is slow and requires a substantial exertion of physicaleffort. While these disadvantages may not be important to the occasionaluser of such saws, it will be apparent that a carpenter or anotherconstant user of such tools would prefer the ease and efficiency of apower operated device. While the conventional saber saw is a power tool,the rapidly reciprocating movement of such saws frequently produces acut which is less uniform and smooth than the cut provided by thekeyhole saw. Yet another disadvantage of such saws is the fact that aseparate starting hole must be provided in the surface to be cut, sothat the saw blade can be inserted to place the cutting teeth in contactwith the surface.

Accordingly, it is an object of the present invention to provide animproved saw.

It is another object of the present invention to provide a power saw ofthe keyhole type.

It is still another object of the present invention to provide a powersaw of the keyhole type which provides unidirectional saw blademovement.

It is still another object of the present invention to provide a saw ofthe keyhole type which is capable of providing its own starting hole incertain materials.

Other objects and many of the attendant advantages of the presentinvention will become more readily apparent from the followingdescription of a working embodiment, including the annexed drawing inwhich:

FIG. [is a plan view partially broken away and showing an embodiment ofa saw according to the present invention;

FIG. 2 is an elevation view of the saw shown in FIG.

FIG. 3 is a section view taken along line 33 of FIG.

FIG. 4 is a fragmentary plan view of an embodiment of the saw blade asused in the saw shown and described herein:

FIG. 5 shows an elevation view of a saw according to a second embodimentof the present invention; and

FIG. 6 shows a partial isometric view of the saw and driving motorattachment according to an embodiment of the present invention.

Stated in general terms, the saw of the present invention includes ablade guide extending outwardly from a blade drive housing and defininga channel along which a bandlike saw blade can move for continuous orunidirectional movement. The saw blade band includes a number of cuttingmembers which extend out wardly of the band at a substantial anglethereto and which include a cutting edge aligned for cutting engagementwith a work piece to be cut by the saw. Motive power for driving the sawblade can be advantageously supplied through an external source such asa portable drill motor coupled to the saw.

More particularly and with reference taken to the embodiment of thepresent invention as shown in FIGS. 1-4, there is shown portable sawapparatus indicated generally at 10 and including a housing showndiagrammatically at 11 having an opening 12 on one side thereof toaccommodate the passage of a blade guide l3 extending outwardly adistance from the housing. The blade guide 13 is adjustably attached tothe housing 11 to permit the distance between the housing and the outerend 14 of the blade guide to be varied for a purpose described below.This adjustable attachment is provided in the disclosed embodimentsthrough a plate 15 secured to the inner end of the blade guide 13 andcontaining a number of elongated slots 16 through which a correspondingnumber of bolts 17 pass for threaded engagement with a suitable locationon the housing 1 1.

The blade guide 13 is constructed to appear in crosssection, as shown inFIG. 3, somewhat like the letter H with an enlarged horizontal memberconnecting the two vertical lines of the II. This construction of theblade guide 13 provides a blade channel having a first channel portion21 and a second channel portion 22, each of which somewhat resembles a Uin cross-section and each of which has a blade support surface 23 and24, respectively. Extending outwardly from the blade support surfaces 23and 24 are side walls 26, 27 and 28,

Disposed within the first and second channel portions 21 and 22 of theblade guide 13 is a saw blade in the form of a continuous band 34 havinga number of periodically-spaced openings 35. It can be seen especiallyin FIG. 2 that the band 34 is a continuous closed loop, and the openings35 are periodically spaced along the entire length of the band. The sawblade includes a plurality of cutting members 36, as best shown in FIGS.3 and 4, which are disposed in staggered spaced apart relation relativeto the band 34. In the disclosed embodiment of the present invention,each of the cutting members 36 is unitary with the band 34 and is formedto have a riser portion 37 extending substantially perpendicularly tothe band 34, and a blade portion 38 disposed in a plane substantiallyparallel with the band 34 and spaced apart therefrom. The forward orcutting edge 39 of each blade portion 38 is suitably sharpened toaccomplish the actual material cutting operation of the saw blade. Eachof the risers 37 extends outwardly slightly from the respective edge ofthe band 34 in the disclosed embodiment. The blade portions 38 aresufficiently long to permit the ends of adjacent blades to overlap, asshown in FIG. 4, although the blades in FIG.

3 are shown deliberately shortened to facilitate illustration of thedisclosed embodiment.

The closed path of the band 34 is additionally defined, in the firstdepicted embodiment of the present invention, by a pair of outside idlerwheels 42 and 43, a pair of inside idler wheels 44 and 45, by a drivewheel 46, and by an inside idler wheel 47 disposed at the outer end 14of the blade guide 13 to operate as a bridge in the path of the bandfrom the first channel portion 31 to the second channel portion 22.Considering first the construction of the drive wheel 46, this wheel hasa peripheral surface 48 including a number of tooth-like projections 49extending radially therefrom. The peripheral spacing of the projections49 is selected to be identical to the spacing between each of theopenings 35 formed in the band 34, and it can be seen that rotation ofthe drive wheel 46 with the toothlike projections 49 engaged in openings35 of the band 34 will impart unidirectional motion to the saw blade.The drive wheel 46 may be journalled for rotation on a fixed shaft 50contained within the housing 11, and rotational movement may be impartedto the drive wheel through a bevel gear 51 meshing with a correspondingbevel gear face 52 associated with the drive wheel 46. The bevel gear 51is attached for rotation with the input shaft 53 which, as shown ingreater detail below, may extend outside of the housing 11 to be securedin the chuck of a power tool such as a conventional portable electricdrill.

As an alternative to the arrangement of bevel gears 51 and 52 shown inFIG. 1, these gears may be replaced by a conventional unitaryright-angle drive unit having an input shaft corresponding to shaft 53and an output shaft connected to rotate the drive wheel 46.

Each of the inside idler wheels 44 and 45 comprises a wheel mounted forrotation as the band 34 passes thereover and having a suitable groove orother indentation disposed around the periphery thereof to acceptpassage of the band and to maintain the proper tracking of the band.

One or both of the wheels 42 and 43 may be resiliently mounted as bysprings 57 and 58. Since each of the outside idler wheels 42 and 43 mustoperate to change the direction of movement of the band 34 withoutcontacting the cutting members 36 which project outwardly from the band,these outside idler wheels have a peripheral surface 60 from which aplurality of land members 61 radially extend a distance which is atleast equal to the distance by which the blade portions 38 of thecutting members 36 are spaced outwardly from the band 34. Each of theland members 61 has a tooth-like projection 62 extending radiallyoutwardly therefrom, with the outwardly-facing peripheral area of eachland member 61 being greater than the area of the correspondingtooth-like projection 62 to provide on each land member an area ofsupport which contacts the outer surface of the band 34 as therespective land member is moved by rotation of the idler wheels 42 and43 into contact with the band. lt will thus be understood that each ofthe cutting members 36 which extends outwardly from the band 34 willpass between two adjacent land members 61 without contacting theperipheral surface 60 of the idler wheel; accurate registration betweenband 34 and the idler wheels 42 and 43 is maintained through engagementof the projections 62 with the openings 35 in the band.

The idler wheel 47 disposed at the outer end 14 of the blade guide 13includes a peripheral surface 65 having a number of tooth-likeprojections 66 extending radially outwardly therefrom, and so it can beseen that the idler wheel 47 resembles a scaled-down version of thedrive wheel 46. As best shown in FIG. 2, the diameter of the peripheralsurface 65 and the placement of the idler wheel 47 in the blade guide 13are chosen so that the bottom 23 of the first channel portion 21 and thecorresponding bottom of the second channel portion 22 are at leastapproximately tangentially aligned with the peripheral surface 65 of theidler wheel 47. This arrangement provides a substantially uniform pathof travel for the band 34 moving outwardly along the second channelportion 22 onto the idler wheel 47 and then back along the first channelportion 21. Although the idler wheel 47 is shown provided withtooth-like projections 46 to insure that this idler wheel rotates toassist movement of the band, these projections 66 can be eliminated ifdesired and the idler wheel 47 can be provided with a grooved peripheralsurface to accommodate passage of the band 34, in the manner describedpreviously with reference to the inside idler wheels 44 and 45.

The spacing of the riser portion 37 is chosen to be greater than thedistance by which the side walls 26 extend outwardly from the bottomsurface 23 of the blade channel. Accordingly, it can be seen thatmovement of the band 34 along the blade guide 13 causes the progressionof forward edges 39 to move extending outwardly of the blade guide, asseen in FIG. 2. These forward edges 39, when brought to bear against awall panel or another work piece to be cut, provide the requisite sawingaction. The space between each of the blade portions 38 and the band 34provides adequate clearance for self-removal of sawdust and otherparticles developed during the sawing process. It can also be seen thatthe blade portions 38 and the forward edges 39 thereof extend outwardlyfrom the idler wheel 47 as the blade passes around that wheel; thisexposed movement of the forward edges 39 at the outer end of the bladeguide 13 provides the saw of the present invention with the capabilityof cutting its own starting opening in surface materials, such asdrywall and relatively thin wood paneling, simply by placing the outerend 14 of the blade guide in firmly held position against the materialto be cut and operating the saw. Installation and removal of the sawblade is accomplished by loosening the bolts 17 and moving the bladeguide inwardly of the housing.

A second disclosed embodiment of the present invention, as seen in FIG.5, provides a somewhat simplified arrangement and construction of thesaw in which only a single inside idler wheel 69 and a single outsideidler wheel 70 are requird. The overall configuration of the sawresembles that of a pistol, and other details of the saw including thedesign of the idler wheels 69 and 70 remain substantially unchanged fromthose described with reference to the first described embodiment of thepresent invention.

Referring now to FIG. 6, a pair of strap members 71 and 72 are pivotallyconnected to opposing sides of the housing 11 at locations 73 and 74thereon. Each of the strap members 71 and 72 includes a first strapportion 71a and 72a, respectively, connected for pivotal movement at therespective locations 73 and 74, and further comprises second strapportions 71b and 72b,

respectively. A plurality of adjustment holes 75 is provided along theportions 71a, 71b and along 72a, 72b, so that the spacing between thehousing 11 and the second portions 71b, 72b can be selectively varied.

Interconnection between the first and second por tions of the strapmembers 71 and 72 is provided with a pair of studs 76 and 77, which arereceived through appropriate aligned holes 75 in the respective strapmember portions, and with a pair of wing nuts one of which is shown at78 and the other of which is hidden from view by the drill motor 83. Thewing nuts also pass through appropriate aligned pairs of holes 75 andthrough respective aligned internally threaded holes in the collarmember 80. A pair of pressure pads, one of which is shown at 81, isswivelably connected to the respective ends of the wing nuts inpositioned relationship to be brought to bear against the sides of asuitable power source such as a conventional portable drill motor 83which is connected through the drill chuck 84 to the shaft 53 of thesaw.

The collar 85 extends beneath the drill 83 for support purposes and, ifconsidered necessary or desirable, a similar collar (not shown) can beprovided to extend around the upper half of the drill motor.

In attaching a conventional drill motor 83 to the saw of the presentinvention in the manner depicted in FIGS. 7 and 8, the chuck 84 of thedrill is first suitably clamped onto the shaft 53 which emerges from thehousing 11 of the saw. The strap members 71 and 72 are then suitablypositioned by means of the first and second portions thereof so that thepressure pads connected to the wing nuts are suitably disposed to betraversed into clamping engagement with respective sides of the drillmotor 83, with this clamping engagement of the drill motor 83 betweenthe strap members 71 and 72, and additionally within the collar 85, thedrill motor is securely affixed into position relative to the housing111 of the saw; the user of the saw can grasp the drill motor 83 withhis right hand (assuming a right-handed user) and can grasp the housing11 with a suitable handle (not shown) to accomplish the desired sawingoperation.

Although the herein-disclosed embodiments of the present invention aredesigned to be used with an external source of power such as a portabledrill motor, it will be understood by those skilled in the art that aselfcontained motor can be disposed within the housing 11 along withsuitable reduction gearing to provide a saw according to the presentinvention which is complete within itself and which need only be pluggedinto a suitable source of electric power for its operation. It will alsobe apparent that various attachments conventionally used with saws, suchas angle-cutting guides and the like, can be applied as well to the sawof the present invention so that special-purpose cuts such as beveledsurfaces and the like can beprovided. As a specific example, adepth-of-cut stop member applied extending outwardly from the bladeguide 13 at a predetermined distance spaced from the end 14 (toward thehousing 11) can define a maximum depth of cut less than the thickness ofthe workpiece, thereby enabling the present saw apparatus to be used asa router.

It will be understood, of course, that the foregoing relates only topreferred embodiments of the present invention and that numerousalterations and modifications may be made therein without departing fromthe spirit and the scope of the invention as contained in the followingclaims.

What is claimed is:

1. Saw apparatus comprising:

housing means;

blade guide means extending from said housing means to terminate at aspaced location therefrom;

saw blade channel means formed along said blade guide means;

saw blade means disposed for sliding movement along said channel meansof said blade guide means;

said saw blade means comprising a substantially flat endless flexibleband member;

said channel means comprising a saw blade support surface forming anelongate slot defined by a blade support surface and by means extendingfrom said blade surface to define wall means of said channel means;

a plurality of cutting members carried by said saw blade means;

each of said cutting members having a cutting edge disposed in spacedapart relation from said band member of said saw blade means to extendsaid cutting edge outside of said channel means for cutting exposure tomaterial positioned adjacent to said blade guide means; and

motive means disposed in said housing means in operative engagement withsaid saw blade means to impart sliding movement of said saw blade meansalong said channel means.

2. Apparatus as in claim 1, wherein:

at least some of said cutting members having a portion of said cuttingedge offset to extend across said wall means and disposed in a planewhich is spaced apart from and substantially parallel to said bandmember, so that said cutting member portions cut a path of width greaterthan the width of said blade guide means.

3. Apparatus as in claim 1, wherein:

said motive means comprises drive wheel means in driving engagement withsaid saw blade means;

said saw blade means having a plurality of drive engagement means spacedat periodically repetitive locations along said band member; and

said drive wheel means having a peripheral region including a pluralityof drive means spaced along said peripheral region for drivingengagement with said drive engagement means of said saw blade means.

4. Apparatus as in claim 1, wherein:

the width of said band member is less than the width of said channelmeans; and

at least some of said cutting members extend out of and laterally ofsaid elongate slot to define a saw blade means width which is greaterthan the width of said band member and greater than the width of saidchannel means.

5. Apparatus as in claim 4, wherein:

said blade guide means comprises an elongate member having a proximalend disposed adjacent to said housing means and a distal end spacedapart from said housing means;

said channel means extending along a first portion of said elongatemember from said proximal end to said distal end and further extendingalong a second portion of said elongate member from said distal end tosaid proximal end,

said first portion and said second portion being in spaced apartrelation to each other; and

means disposed at said distal end of said elongate member providing sawblade sliding movement interconnection between said first and secondportions of said channel means.

6. Apparatus as in claim 5, further comprising:

drive wheel means in driving engagement with said band member and havinga peripheral region including a plurality of drive means spaced alongsaid peripheral region for driving engagement with said band member;

said drive wheel means having a diameter substantially greater than thespacing between said first and second portion of said elongate member;

at least one idler wheel means positioned between said drive wheel meansand said proximal end of said elongate member;

said idler wheel means having a peripheral region disposed to besubstantially tangentially aligned with one of said first and secondportion of said channel means; and

said band member being disposed in engagement with said peripheralregion of said idler wheel .means to be in substantial alignment withsaid one portion of said channel means.

7. Apparatus as in claim 6, wherein:

said peripheral region of said idler wheel means comprises a pluralityof spacer members separated from each other along the circumference ofthe idler wheel means by undercut regions of sufficient depth to receivesaid cutting members extending from said saw blade means; and

each of said spacer members has band member engaging means disposedthereon for engagement with said band member.

8. Apparatus as in claim 5, further comprising:

adjustable means interconnecting said elongated member and said housingmeans to vary the spacing between said housing means and said distalend.

9. Apparatus as in claim 1, wherein:

said motive means includes a drive member extending from said housingmeans for connection with a drive motor;

first pair of spaced apart connective members extending from attachmentto said housing means to a spaced apart location therefrom;

second pair of spaced apart connective members selectivelyinterconnected with said first pair of connective members to enable saidsecond pair of connective members to terminate at a selectivelyadjustable distance from said housing means; and

engagement means connected to at least one of said pairs of spaced apartconnective members and positioned there-between to holdingly engage adrive motor connected to said coupling means.

10. Apparatus as in claim 9, further comprising:

support means extending between at least one pair of said connectivemembers to form a collar for supporting the drive motor; and

each of said second pair of connective members having a portionextending rearwardly from said selective interconnection and intoengagement with an exterior location on the drive motor.

1. Saw apparatus comprising: housing means; blade guide means extendingfrom said housing means to terminate at a spaced location therefrom; sawblade channel means formed along said blade guide means; saw blade meansdisposed for sliding movement along said channel means of said bladeguide means; said saw blade means comprising a substantially flatendless flexible band member; said channel means comprising a saw bladesupport surface forming an elongate slot defined by a blade supportsurface and by means extending from said blade surface to define wallmeans of said channel means; a plurality of cutting members carried bysaid saw blade means; each of said cutting members having a cutting edgedisposed in spaced apart relation from said band member of said sawblade means to extend said cutting edge outside of said channel meansfor cutting exposure to material positioned adjacent to said blade guidemeans; and motive means disposed in said housing means in operativeengagement with said saw blade means to impart sliding movement of saidsaw blade means along said channel means.
 2. Apparatus as in claim 1,wherein: at least some of said cutting members having a portion of saidcutting edge offset to extend across said wall means and disposed in aplane which is spaced apart from and substantially parallel to said bandmember, so that said cutting member portions cut a path of width greaterthan the width of said blade guide means.
 3. Apparatus as in claim 1,wherein: said motive means comprises drive wheel means in drivingengagement with said saw blade means; said saw blade means having aplurality of drive engagement means spaced at periodically repetitivelocations along said band member; and said drive wheel means having aperipheral region including a plurality of drive means spaced along saidperipheral region for driving engagement with said drive engagementmeans of said saw blade means.
 4. Apparatus as in claim 1, wherein: thewidth of said band member is less than the width of said channel means;and at least some of said cutting members extend out of and laterally ofsaid elongate slot to define a saw blade means width which is greaterthan the width of said band member and greater than the width of saidchannel means.
 5. Apparatus as in claim 4, wherein: said blade guidemeans comprises an elongate member having a proximal end disposedadjacent to said housing means and a distal end spaced apart from saidhousing means; said channel means extending along a first portion ofsaid elongate member from said proximal end to said distal end andfurther extending along a second portion of said elongate member fromsaid distal end to said proximal end, said first portion and said secondportion being in spaced apart relation to each other; and means disposedat said distal end of said elongate member providing saw blade slidingmovement interconnection between said first and second portions of saidchannel means.
 6. Apparatus as in claim 5, further comprising: drivewheel means in driving engagement with said band member and having aperipheral region including a plurality of drive means spaced along saidperipheral region for driving engagement with said band member; saiddrive wheel means having a diameter substantially greater than thespacing between said first and second portion of said elongate member;at least one idler wheel means positioned between said drive wheel meansand said proximal end of said elongate member; said idler wheel meanshaving a peripheral region disposed to be substantially tangentiallyaligned with one of said first and second portion of said channel means;and said band member being disposed in engagement with said peripheralregion of said idler wheel means to be in substantial alignment withsaid one portion of said channel means.
 7. Apparatus as in claim 6,wherein: said peripheral region of said idler wheel means comprises aplurality of spacer members separated from each other along thecircumference of the idler wheel means by undercut regions of sufficientdepth to receive said cutting members extending from said saw blademeans; and each of said spacer members has band member engaging meansdisposed thereon for engagement with said band member.
 8. Apparatus asin claim 5, further comprising: adjustable means interconnecting saidelongated member and said housing means to vary the spacing between saidhousing means and said distal end.
 9. Apparatus as in claim 1, wherein:said motive means includes a drive member extending from said housingmeans for connection with a drive motor; first pair of spaced apartconnective members extending from attachment to said housing means to aspaced apart location therefrom; second pair of spaced apart connectivemembers selectively interconnected with said first pair of connectivemembers to enable said second pair of connective members to terminate ata selectively adjustable distance from said housing means; andengagement means connected to at least one of said pairs of spaced apartconnective members and positioned there-between to holdingly engage adrive motor connected to said coupling means.
 10. Apparatus as in claim9, further comprising: support means extending between at least one pairof said connective members to form a collar for supporting the drivemotor; and each of said second pair of connective members having aportion extending rearwardly from said selective interconnection andinto engagement with an exterior location on the drive motor.